Apparatus and method for soil tillage and levelling

ABSTRACT

A tillage apparatus includes a wheeled frame configured with a plurality of concave blades arranged in a plurality of longitudinally extending columns and transversely extending rows. The rows are longitudinally spaced apart by a progressively increasing distance. The blades of each column are transversely tilted alternately to the left and right. The blades of each column are transversely offset from one another to create a swath of tilled ground along the width of the column. In operation, soil is thrown left and right between successive blades of a column to till the soil across the width of the column and leave a substantially level soil surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation under 37 CFR 1.53(b) of currentlypending U.S. patent application Ser. No. 13/840,996 filed Mar. 15, 2013,the entire content of which is hereby incorporated by reference.

TECHNICAL FIELD

This disclosure relates to agricultural equipment, and moreparticularly, to tillage implements and tillage methods.

BACKGROUND

A tillage implement equipped with rows of spaced apart individuallymounted coulter wheel assemblies is known in the art for use inconservation tillage. An example is provided in commonly owned U.S. Pat.No. 7,762,345, which is incorporated herein by reference.

Some coulter wheel assemblies are known to use springs having ahorizontal spring axis, such as is shown in commonly owned U.S. Pat. No.6,412,571, which is incorporated herein by reference.

An example of a tillage implement comprising spaced apart rows ofindividually mounted tillage blade assemblies having a concave discblade and a shank with a spring having a horizontal spring axis isprovided in commonly owned US patent application published as US2011/0132628, which is incorporated herein by reference.

An example of a blade assembly and tillage implement equipped therewithcomprising a resilient element in place of the coil spring is providedin commonly owned US patent application published as US 2011/0132627,which is incorporated herein by reference.

In conventional tillage operations using implements equipped withconcave disc shaped tillage blades (for example, disc harrows), the soilis turned at the site of the disc and crop residue between the discs isburied by thrown soil. In such conventional tillage implements, the discshaped blades are normally oriented with the concave side of adjacentdiscs facing the same direction. For example, referring to prior artFIG. 9, a disc harrow is equipped with a first set of concave discshaped blades 300 mounted on a first common gang shaft 301 with theconcave side of the blades facing towards the center of the implement,while a second set of concave disc shaped blades 310 is mounted on asecond common gang shaft 311 with their concave sides facing away fromthe center of the implement. This causes soil to be transferred eithertowards the center of the implement, leaving a ridge, or away from thecenter, leaving a valley. In practice, a more acute angle between thegang shafts 301, 310 and the direction of travel of the implement leadsto greater soil throw and greater coverage of crop residue between thedisc shaped blades, but also leads to larger center ridges and largervalleys at the outside edges of the disc harrow. The farmer is thereforealways forced to strike a compromise between effective crop residuecoverage and the levelness of the soil surface following tillage.

There is a need for improved tillage implements and methods of usethereof that provide both effective crop residue coverage and a levelsoil surface following tillage.

SUMMARY

The tillage implements and tillage methods described herein areconfigured with sets of four or more longitudinally spaced apart tillageblades that co-operate with one another to alternately direct soil tothe left and right transversely and rearwardly with respect to thedirection of travel of the implement. Each blade is concave and isangled with respect to the vertical direction and the direction oftravel of the implement by a pre-determined amount. The amount ofrearward direction of the soil increases with each successive blade inthe set of four or more tillage blades. This causes the soil to beprogressively spread out and leveled as it passes through the implement,thereby both tilling and leveling the soil. This leveling effectdesirably mitigates the aforementioned difficulties in maintaining alevel soil surface encountered during use of, for example, a discharrow.

BRIEF DESCRIPTION OF THE DRAWINGS

Having summarized the invention, embodiments thereof will now bedescribed with reference to the accompanying figures, in which:

FIG. 1 shows a perspective view of an embodiment of a tillage apparatus;

FIG. 2 shows a plan view of the tillage apparatus of FIG. 1;

FIG. 3 shows an enlarged plan view of one side of the tillage apparatusof FIG. 1;

FIG. 4 shows a side view of the tillage apparatus of FIG. 1;

FIG. 5 shows a top view of a concave disc shaped tillage blade;

FIG. 6 shows a front view of the blade of FIG. 5;

FIG. 7 shows a side view of the blade of FIG. 5; and,

FIG. 8 shows a plan view of a tillage apparatus according to anotherembodiment.

DETAILED DESCRIPTION

Referring to FIG. 1, a tillage apparatus 10 comprises a generallyrectangular frame 12 formed of a plurality of longitudinal 14 andtransverse 16 rectangular steel tubes. The tillage apparatus 10comprises a central portion, generally denoted as 18, and two wingportions, generally denoted as 20. The tubes 14, 16 of each portion 18,20 are welded together. Each wing portion 20 is attached to a side ofthe central portion 18 by hinges 22. Each wing portion 20 has one ormore hydraulic cylinders 24 mounted to the central portion 18 andoperatively connected to each wing portion 20. Each wing portion 20 isable to pivot from a horizontal ground working orientation to a verticaltransport orientation upon actuation of the respective hydrauliccylinder 24.

The tillage apparatus 10 includes a plurality of rows 26 a-d of tillageblade assemblies 90, each comprising a concave tillage blade 28. In thisembodiment, the number of rows 26 a-d is four, although more or fewermay be used in other embodiments. The rows 26 a-d are spaced apart alonga longitudinal (or forward) direction F and extend in a direction T thatis transverse (left/right) to the direction F. Each of the concaveblades 28 is individually rotatably attached to the tillage bladeassembly 90, which is mounted to the frame 12. When the tillageapparatus 10 is moved in the forward direction F by a towing vehicle,such as a tractor, the concave blades 28 engage the ground to cut,scoop, and throw soil. The concave blades 28 will be discussed in moredetail below.

In this embodiment, the tillage apparatus 10 further includes at leastone stabilizer blade 29 rotatably attached to the frame 12 by a suitableblade mounting structure. The stabilizer blade 29 is a non-concave bladethat has a transverse axis of rotation about which the stabilizer blade29 is rotatable in the forward direction F to serve to guide andstabilize movement of the tillage apparatus 10 across the ground. Thestabilizer blade 29 may assist the tillage apparatus 10 from transversewandering induced by a tendency for rearward concave blades 28 to pullinto troughs cut by forward concave blades 28. The stabilizer blade 29may have a wavy-edged disc shape or another shape, such as a flat discshape. In this embodiment, two stabilizer blades 29 are positioned at ornear the transverse extents of the tillage apparatus 10.

The tillage apparatus 10 has at least one rearward set of wheelscomprising central wheels 30 mounted to the central portion 18 and wingwheels 32 mounted to the wing portions 20. The wheels 30, 32 arearranged to allow rolling movement of the tillage apparatus 10 in theforward direction F. In the embodiment shown, the wheels 30, 32 are eachprovided as a pair of tandem wheels and are transversely spaced apart tospread the weight of the apparatus in order to prevent rut formation.The wheels 30, 32 may be forwardly spaced apart as well. The wheels 30,32 may be configured in a walking axle arrangement. A walking axlearrangement allows the tillage apparatus 10 to accommodate variations inthe soil surface by permitting the wheels 30, 32 to travel overobstacles without lifting the tillage apparatus 10 to the same degree aswould occur without walking axles. The wheels 30, 32 areheight-adjustable to set the operational depth of the blades 28. In thisembodiment, the wheels 30, 32 are located at a position forward of arearmost row 26 d of concave blades 28 and rearward of a row 26 cadjacent the rearmost row 26 d. Advantages associated with this wheelplacement will be further described hereinafter. In this embodiment, twopairs of wheels 30 are mounted to the central portion 18 of the frame 12and one pair of wheels 32 is mounted to each wing portion 20 of theframe 12.

The tillage apparatus 10 further includes one or more forward wheels 34mounted to the frame 12 at a position forward of a forward-most row 26 aof concave blades 28 and arranged to permit movement of the tillageapparatus 10 in the forward direction F. Each of the forward wheels 34is height-adjustable. Each of the forward wheels 34 may be a casterwheel that is able to rotate about a vertical axis in response todirectional changes of the apparatus. In this embodiment, one forwardwheel 34 is mounted to each wing portion 20 of the frame 12. The forwardwheels 34 advantageously maintain the rectangular frame 12 in a desiredangular orientation with respect to the soil surface and preventinadvertent digging of the front row 26 a of tillage blades into thesoil surface when ruts are encountered in the field.

The tillage apparatus 10 has a coupling mechanism 36 at the frontthereof for hitching the tillage apparatus 10 to the drawbar of avehicle, such as a tractor (not shown). The coupling mechanism 36 ispivotally attached to the central portion 18 of the frame 12 at a tonguehinge 38. The angle of the coupling mechanism 36 with respect to thetillage apparatus 10 can be made adjustable by use of an adjustingmechanism (not shown). The front wheels 34 therefore allow theorientation of the frame 12 to be set relative to the soil surface,irrespective of the orientation of the coupling mechanism 34.

The tillage apparatus 10 can further include rear-mounted levelingattachments that can be attached to a rear of the frame 12. An optionalset of spike harrows (not shown) and/or an optional set of rollingharrows (not shown) may be connected to the rear of the tillageapparatus 10. When both sets of harrows are provided, the rollingharrows may be provided rearward of the spike harrows. Thisconfiguration serves to further level the ground and break up any lumpsof soil that may have been created by the concave blades 28,particularly in wet conditions.

FIG. 2 shows a plan view of the tillage apparatus 10 showing anarrangement of concave blades 28. In the following description, concaveblades may be referred to generally with reference numeral 28 and may bereferred to specifically based on row using reference numerals 28 a-d.This is for the sake of clarity and is not intended to be limiting.

The concave blades 28 are aligned in transversely extending rows 26 a-din a plurality of side by side longitudinally extending columns 50, 50′.The concave blades 28 a-d in a given column 50, 50′ are transverselyoffset from one another to create a swath of tilled ground along atransverse width of the column 50, 50′.

The concave blades 28 a-d of a given row 26 a-d do not need to form astraight line and can be somewhat offset from one another in thelongitudinal direction, denoted by arrow F. For example, referring torow 26 a, an outermost concave blade 28 b is rearward of the adjacentconcave blade, denoted 52, in the same row 26 a.

The columns 50, 50′ of concave blades 28 are positioned in a mirroredarrangement about a longitudinally aligned central axis 54 of thetillage apparatus 10. That is, blades 28 in columns 50 on one side ofthe central axis 54 are positioned and tilted with mirrored symmetrywith respect to blades 28 in columns 50′ on the other side of thecentral axis 54. This can help the tillage apparatus 10 pull straightforward across the ground and reduce or eliminate any tendency for thetillage apparatus 10 to pull transversely left or right.

The concave blades of a given column 50, 50′ are transversely tiltedleft or right alternately by row 26 a-d in order to cut, scoop, and thenthrow tilled soil transversely back and forth as the tillage apparatus10 is pulled forward. That is, for any given column 50, 50′, the concaveblade 28 a faces outwardly away from the central axis 54 of the tillageapparatus 10, while the concave blade 28 b behind the concave blade 28 afaces inwardly. Likewise, the next concave blade 28 c faces outwardlyand the rearmost concave blade 28 d faces inwardly. Tilled ground isthus tossed outwardly, inwardly, outwardly, and inwardly again as it isthrown between the concave blades 28 a, 28 b, 28 c, 28 d. By throwingthe soil back and forth in this manner, any clumps of material arebroken up; this results in less ribboning in the finished groundsurface. This desirably creates a more level tilled soil surface.

It will be evident to those skilled in the art that substantially thesame effect could be achieved if the blades were oriented oppositely tothe orientation described herein. However, by configuring the lead row26 a, to have its concave blades 28 a facing outwards, away from thecentral axis 54, accumulation of material near the central axis 54 isadvantageously reduced where they blades have maximum angle with respectto the longitudinal direction, which reduces the chance of plugging ofsoil flow through the implement and creating a large ridge. Therefore,the configuration shown is especially desirable compared with theopposite configuration.

The mirrored symmetry of columns 50, 50′ of blades 28 about the centralaxis 54 may result in a central geometric discontinuity in or around acentral region 56. Tillage of ground in the central region 56 can befacilitated by central pairs of concave blades 58, 60. In thisembodiment, the concave blades 58 are forward of the concave blades 60.The concave blades 58 are closer to the central axis 54 than are theconcave blades 60. The transverse spacing between the concave blades 58is less than the transverse spacing between the concave blades 60, whilethe longitudinal spacing between the concave blades 58 is greater thanthe longitudinal spacing between the concave blades 60. The concaveblades 58 are tilted to face outwardly, away from the central axis 54,while the concave blades 60 are tilted to face inwardly towards thecentral axis 54. One result of this arrangement of the central concaveblades 58, 60 is that tilled ground in the central region 56 is thrownoutwardly before being thrown inwardly, which advantageously leads togreater spreading and leveling of soil, resulting in more even tillagein the central region 56.

The spacing of the rows 26 a-d in the longitudinal direction can beselected to improve tillage and reduce the chance of plugging or seizingof blades 28. Row spacing can be selected in a manner so that thespacing between a rearward adjacent pair of rows is greater than thespacing between a forward adjacent pair of rows. Accordingly, thespacing between second and third rows 26 a, 26 c is greater than thespacing between first and second rows 26 a, 26 a.

In this embodiment, the spacing between third and fourth rows 26 c, 26 dis also greater than the spacing between second and third rows 26 a, 26c. However, in another embodiment, the spacing between third and fourthrows 26 c, 26 d is substantially the same as the spacing between secondand third rows 26 a, 26 c. In still another embodiment, the wheels 30,32 are positioned between the second and third rows 26 a, 26 c and thespacing between the second and third rows 26 a, 26 c is accordinglygreater than the spacing between the third and fourth rows 26 c, 26 d.This will be described in greater detail hereinafter with reference toFIG. 8.

Also shown in FIG. 2 is a central stabilizer blade 62 located at thecentral axis 54. The central stabilizer blade 62 is similar to thepreviously described stabilizer blades 29 and the related descriptioncan be referenced.

In this embodiment, the blades 28 a-d of the rows 26 a-d and thecentrally located blades 58, 60 are all transversely tilted concaveblades. In another embodiment, the blades of the rearmost row 26 d canbe wavy blades that are not transversely tilted and similar to thestabilizer blades 29, 62.

Further detail regarding the arrangement of blades 28 will now bediscussed with respect to FIG. 3, which shows a plan view of one side ofthe tillage apparatus 10. It should be understood that the descriptionbelow also applies to the opposite side, not depicted in FIG. 3.

Referring to the column 50′, the concave blades 28 b and 28 c in thesecond and third rows 26 a, 26 c, are positioned at opposite transverseextents of the width of the column. In addition, these two concaveblades 28 b, 28 c are in adjacent rows and oppositely transverselytilted with respect to each other. The forward concave blade 28 b isinwardly transversely tilted and the rearward concave blade 28 c isoutwardly transversely tilted. Adjacent columns may transverselyoverlap, so that some portion of ground is tilled by blades 28 of bothcolumns.

Still referring to column 50′, the first row 26 a is outwardly offsetfrom the third row 26 c, and the fourth row 26 d is inwardly offset fromthe second row 26 a. In this example, the width of the column 50′ is20-inch (or 52 cm). The rows 26 a-d are evenly offset within this pitch,such that blades 28 a-d of each row are transversely offset from eachother by an offset distance equal to the column width divided by thenumber of rows, which in this example is 5 inches (or 13 cm). The columnwidth and offset dimensions discussed are but one illustrative example.

Depending on the column width, offset of the blades 28, diameter of theblades and the depth at which they are set, two transversely adjacentconcave blades 28 may be separated by a transverse gap in which groundis not directly contacted by any of the concave blades 28. However, thearrangement of the blades 28 as described herein advantageously tillsthe soil in such a gap due to direct tillage of adjacent soil by nearbyconcave blades 28 and throwing of soil over the untilled gap.

As mentioned above, the forward spacing between the rows 26 a-d can beselected so that the spacing between a rearward adjacent pair of rows isgreater than the spacing between a forward adjacent pair of rows. Sincetilled soil is thrown from a forward concave blade 28 into the path ofrearward concave blade 28, such spacing can advantageously allow thrownmaterial to disperse across the ground in order to reduce the chancethat blades 28 receiving thrown material will become plugged. In thisembodiment, longitudinal row spacing may be selected so that the spacingbetween a forward adjacent pair of rows is between about 1 and about 1.5times the overall diameter of the blades 28 and the spacing between arearward adjacent pair of rows is between about 1.5 and about 4 timesthe overall diameter of the blades 28. For example, the spacing betweenthe first and second rows 26 a, 26 a can be between about 1 and about1.5 times the overall diameter of the blades 28, and can in this examplebe about 1.2 times the overall diameter of the blades 28. Accordingly,the spacing between the second and third rows 26 a, 26 c can be betweenabout 1.5 and about 4 times the overall diameter of the blades 28, andcan in this example be about 1.9 times the overall diameter of theblades 28. Likewise, the spacing between the third and fourth rows 26 c,26 d can be between about 1.5 and about 4 times the overall diameter ofthe blades 28, and can in this example be about 3.7 times the overalldiameter of the blades 28.

In another embodiment, the spacing between a forward adjacent pair ofrows is between about 1 and about 1.5 times the overall diameter of theblades 28, while the spacing between a rearward adjacent pair of rows isbetween about 1.5 and about 2.5 times the overall diameter of the blades28. In such embodiment, the wheels 30, 32 can be located elsewhere, suchas at the transverse extents of the apparatus 10, if there is not enoughspace among the blades 28 to accommodate them.

The concave blades 28 a-d may be transversely tilted by differentangular amounts based on their longitudinal position on the apparatus.That is, while the blades 28 a-d in a given row may be transverselytilted by the same angle, the blade angles used for successive rows 26a-d may be different. In one embodiment, the transverse tilt angle A ofthe rows 26 a-c are the same and greater than the transverse tilt angleB of the rearmost row 26 d. Since no concave blades follow the rearmostrow 26 d, the reduced transverse tilt angle B of the blades in therearmost row 26 d can advantageously result in less transversedisplacement of soil by the blades 28 d of the rearmost row 26 d. In oneexample, the transverse tilt angle A is about 16 degrees and thetransverse tilt angle B is about 8 degrees, or about half the angle A.

Regarding the flow of tilled soil when the tillage apparatus 10 is inmotion, each concave blade 28 a in the forward-most row 26 a throwssoil, at 70, towards the respective concave blade 28 b in the second row26 a. Most of the thrown soil lands on or lands in the path of theconcave blade 28 b, which in turn throws, at 72, most of such material,as well as additional soil cut and scooped by the concave blade 28 b,towards the respective concave blade 28 c in the third row 26 c. Theconcave blade 28 c throws, at 74, such material, as well as additionalsoil cut and scooped by the concave blade 28 c, towards the respectiveconcave blade 28 d of the rearmost row 26 d. Most of the material thrownby the concave blade 28 c lands on or lands in the path of the rearmostconcave blade 28 d, which throws, at 76, such material, as well asadditional soil cut and scooped by the concave blade 28 d, into asubstantially level surface rearward of the implement.

In addition, because of the blade arrangement described herein, aconcave blade 28 a-d can advantageously keep a neighboring concave blade28 a-d in the same row 26 a-d free of built-up ground material, whichmay collect on the backs of concave blades 28 a-d particularly when theground is wet. This principle applies to any of the concave blades 28a-d that have a neighboring concave blade 28 a-d at their back. Itshould be noted that each of the outermost concave blades 28 b of thesecond row 26 a is offset rearward from other concave blades 28 b in thesame row, because each blade 28 b receives a significant amount ofthrown material from the respective concave blade 28 a in the forwardrow 26 a, but the outermost blade 28 b does not have a neighboringconcave blade to provide this cleaning effect. The relatively smallrearward offset of each of the outermost concave blades 28 b can reducethe amount of thrown material reaching the backside of the blade andthus reduces the chance of material build-up clogging the back side ofthe blade. The outermost concave blades 28 c-d of the rows 26 c-d arenot offset in this manner, as the spacing of each of these rows 26 c-dwith respect to the row ahead is large enough to reduce the risk ofdetrimental material build-up on the back side of the blade.

FIG. 4 shows a side view of the tillage apparatus 10. Some componentsare omitted from this view for clarity.

The tillage apparatus 10 includes at least one depth-adjustmentmechanism 80 for the rearward wheels 30, 32 in order to control thedepth of tillage D. Each depth-adjustment mechanism 80 includes an arm82 that is pin-connected, at 84, to a bracket that is fixed to the frame12. The hubs of one or more wheels 30, 32 are connected to an oppositeend of the arm 82. A hydraulic cylinder 88 is pin-connected between thehubs of the one or more wheels 30, 32 and a pillar 86 extending upwardsfrom the frame 12. When the hydraulic cylinder 88 is retracted, thewheels 30, 32 are moved further into the accommodating space of theframe 12, the frame 12 is lowered, and the depth of tillage D isincreased. When the hydraulic cylinder 88 is extended, the wheels 30, 32are pushed out of the accommodating space of the frame 12, the frame 12is raised, and the depth of tillage D is decreased. The hydrauliccylinder 88 may include a damper to reduce vibrational effects of unevenground on the frame 12 during use. In this embodiment, pairs of wheels30, 32 are provided with one depth-adjustment mechanism 80.

In this embodiment, the depth-adjustment mechanisms 80 allows for aselectable depth of tillage D of between about 1 and about 6 inches(about 2.5 to 15 cm).

The forward wheels 34 can be provided with a depth-adjustment mechanismsimilar to the depth-adjustment mechanism 80 or with a differentdepth-adjustment mechanism. Alternatively, the wheels 34 are notheight-adjustable.

Configuring the apparatus 10 with wheels 30, 32 between the third andfourth rows 26 c and 26 d causes forward weight transfer onto the hitch.This weight transfer is accepted by the forward wheels 34, which can beindependently depth adjusted to control the amount of “bite” of theforward rows 26 a, 26 a in order to throw more or less soil, asdetermined by the farmer in accordance with the tillage objectives andsoil conditions. In addition, configuring the apparatus 10 withlongitudinally spaced apart forward wheels 34 and rear wheels 30, 32provides a more uniform ride across rough ground, ultimately providinggreater control over tillage depth. Therefore, this wheel configurationprovides for improved tillage performance and soil leveling.

FIG. 5 shows one of the concave blades 28 from above. Each concave blade28 is part of a blade assembly 90 that includes the concave blade 28, ablade hub 92, a blade arm 94, and a blade mount 96.

The concave blade 28 is removably mounted to the blade hub 92 by way ofbolts 98. The blade hub 92 can include a lubricated bearing to reducerotating resistance. The blade hub 92 is attached to the blade arm 94 ina manner that permits rotation of the blade 28. The blade arm 94 isattached to the blade mount 96, which is removably connected to atransverse member 16 of the frame 12 (FIG. 1) by way of, for example,U-bolts 99. The transverse position of the concave blade 28 with respectto other concave blades 28 can be adjusted using the U-bolts 99. TheU-bolts 99 also permit the blade assembly 90 to be removed from theframe 12 for maintenance or replacement.

The blade arm 94 is shaped to transversely tilt the blade 28, asindicated by angles A, B discussed above. The material and size of theblade arm 94, and particularly its cross-section, can be selected topermit transverse deflection of the blade arm 94 and thus the attachedblade 28 to advantageously reduce the chance or amount of damage to theblade 28 due to impact with obstacles, such as rocks, while in use.However, the material and size of the blade arm 94 can also be selectedto limit such deflection in order to mitigate the tendency of the blade28 to pull into grooves in the ground cut by blades ahead. In thisembodiment, the blade arm 94 is made of steel and has a rectangularcross-section that is sized to keep transverse deflection to withinabout 0.25-1 inch (6.25-25 mm) under normal loads experienced duringnormal tilling operations.

As mentioned previously, in this embodiment, the transverse tilt angleA, B of the concave blade 28 can be about 16 degrees for rows 26 a-c andabout 8 degrees for rearmost row 26 d. In other embodiments, thetransverse tilt angle for a concave blade 28 not in the rearmost row canrange from about 12 degrees to about 20 degrees, while the transversetilt angle for a concave blade 28 in the rearmost row can range fromabout 4 degrees to about 12 degrees. Larger transverse tilt angles canmean a wider swath of tillage by a given blade 28, but can also meangreater resistance to pulling and a greater tendency to pull the tillageapparatus 10 sideways.

FIG. 6 shows one of the concave blades 28 from the front. As can beseen, the concave blade 28 is tilted from the vertical by an angle C.This assists in the concave blade 28 scooping up ground material at aregion 100 where it cuts into the ground. To an extent, the greater thevertical tilt angle C, the greater the amount of ground material thatcan be scooped up and then thrown. However, increased vertical tiltangle C can also increase resistance to pulling. In this embodiment, thevertical tilt angle is about 16 degrees for blades 28 a-c in forwardrows 26 a-c, and the vertical tilt angle is about 8 degrees for blades28 d in the rearmost row 26 d. In other embodiments, the vertical tiltangle for a concave blade 28 not in the rearmost row can range fromabout 12 degrees to about 20 degrees, while the vertical tilt angle fora concave blade 28 in the rearmost row can range from about 4 degrees toabout 12 degrees. The vertical tilt angle C and transverse tilt anglesA, B for a given blade 28 a-d can be the same or can be different.

Also shown in FIG. 6 is the impingement of thrown soil, at 78, on thebackside of the concave blade assembly 90, as discussed above. Impingingmaterial can help keep the concave blade assembly 90 free of materialbuilt up, particularly between the blade 28 and the blade arm 94, at102, because impinging material has high enough kinetic energy to itselfnot become built up on the blade assembly 90 and further to dislodge anyalready built-up material. Material impingent, at 78, is thusadvantageous, since material build up may result in the blade 28 seizingand thus stopping to rotate, which would require the tillage apparatus10 to be stopped and cleaned manually.

FIG. 7 shows one of the concave blades 28 from the concave side. As canbe seen, the blade mount 96 includes an upper hinge part 110 and a lowerhinge part 112 that are pin-connected together at 114. The upper hingepart 110 is held to the transverse tube 16 by the U-bolts 99. The bladearm 94 is fixed to the lower hinge part 112. The upper and lower hingeparts 110, 112 form an acute angle in which a resilient part 116 issandwiched. The resilient part 116 can include a piece of elastomericmaterial, a metal coil spring, or the like. An adjustable stop pin 118extends between the upper and lower hinge parts 110, 112 to limit theamount that the hinge formed by the upper and lower hinge parts 110, 112can open.

In this embodiment, the stop pin 118 is thread connected, at 120, to theupper hinge part 110. Such a threaded connection can be via a bolt thatthreads into a central threaded bore of the stop pin 118, the boltextending through an opening in the upper hinge part 110 against which ahead of the bolt abuts. Similarly, the stop pin 118 extends through anopening in the lower hinge part 112 and has an enlarged head 122 thatabuts the lower hinge part 112 on the lower side of the opening torestrict movement of the lower hinge part 112 with respect to the upperhinge part 110, which tends to open the hinge. A bolt threaded into thestop pin 118 can be turned to adjust the maximum amount that the hingeis permitted to open. However, the lower hinge part 112 is free to moveaway from the enlarged head 122 of the stop pin 118, in a direction thatcloses the hinge, as the resilient part 116 is compressed during tillageoperations.

The resilient movement of the concave blade 28 as provided for by theresilient part 116 and as limited by the adjustable stop pin 118 canadvantageously reduce the chance and amount of damage to the blade 28during operation, while maintaining an accurate depth of tillage to theground. Such structure also allows the tillage apparatus to be operatedat relatively high rates of speed while reducing the damage to theconcave blades 28 when obstacles, such as rocks, are struck.

Other suitable designs for blades and tillage assemblies usable with thetillage apparatus 10 are described in the published US patentapplications and patents mentioned above.

FIG. 8 shows another embodiment of a tillage apparatus 210. The tillageapparatus 210 is similar to the tillage apparatus 10. Differencesbetween the tillage apparatus 210 and the tillage apparatus 10 will bediscussed in detail below. For further description of features andaspects of the tillage apparatus 210, the description of the tillageapparatus 10 can be referenced. Features and aspects of the tillageapparatus 10 can be used with the tillage apparatus 210.

The tillage apparatus 210 includes a frame 212 made of longitudinallyaligned members 214 and transversely aligned members 216. Thedescription for frame 12 and members 14, 16 may be referenced forfurther detail.

The tillage apparatus 210 further includes wheels 230, 232. Two sets ofinner wheels 230 are arranged in pairs, with each pair configured with awalking axle 233. Two outer wheels 232 are positioned outward of thewheels 230. The description for the wheels 30, 32 may be referenced forfurther detail.

The tillage apparatus 210 further includes a coupling mechanism 236 forpulling the tillage apparatus and the above-described coupling mechanism36 may be referenced.

In this embodiment, the tillage apparatus 210 includes four stabilizerblades 29 positioned at the four corners of the frame 212. The tillageapparatus 210 also includes a plurality of concave blades 28individually attached to the frame 212 and arranged in four rows 226a-d.

The blades 28 are arranged in longitudinaly aligned columns 250. Theblades 28 in each row 226 a-d are transversely tilted opposite theblades in an adjacent row 226 a-d. In this embodiment, the blades 28 ofthe forward-most row 226 a are transversely tilted in the same direction(right) as the blades 28 of the rearmost row 226 d, while the blades 28of the inner two rows 226 a-c are transversely titled opposite (left) tothe blades 28 of the rows 226 a, 226 d. In this embodiment, all of theblades 28 are transversely tilted the same amount. The blades 28 arealso vertically tilted.

In addition, a forward pair of adjacent rows 226 a-226 a are spacedapart by a distance less than the spacing between a rearward pair ofadjacent rows 226 a-226 c.

As can be seen, the blades 28 of the tillage apparatus 210 are notsymmetrically arranged in the same manner as in other embodiments.However, transverse pulling of the tillage apparatus 210 can bemitigated by having approximately equal numbers of blades 28 facing leftand right. Also, due to the lack of symmetry, the tillage apparatus 210does not have a central discontinuous region 56 and thus does not havecentral blades 58, 60 as previously described with reference to thefirst embodiment.

It should be noted that in many embodiments discussed herein, the numberof blades transversely titled in one direction (e.g., left) is aboutequal to the number of blades in the opposite direction (e.g., right).

The tillage apparatus can advantageously be pulled at relatively highspeeds of about 6 to 12 mph (about 10 to 20 km/hr), depending on groundconditions including soil wetness and the amount of crop residue presentin or on the soil, as well as the desired soil surface finish. This isdue to the mirrored symmetry of blades functioning to pull the tillageapparatus straight, and the concave shape and vertical tilt of theblades tending to pull the frame, and thus blades, towards the ground ina manner that increases with increased speed. This can alleviate theneed to add weight to the tillage apparatus to maintain operationalcontact with the ground at higher speeds. Moreover, impingement ofmaterial on a blade from a neighboring blade keeps the blades clean in amanner that also increases with increased speed. The tillage apparatustherefore allows a field to be tilled in less time.

The arrangement, tilting, and mounting structure of the concave bladesas described above causes a reduction in forces that would tend to twistor break the blades, while still allowing a significant amount of groundmaterial to be thrown. Moreover, rearward blades are prevented fromtracking in ruts cut by blades ahead. In addition, the arrangement andtilt of the concave blades, particularly the mirrored nature of thearrangement, reduces the undesirable tendency for the tillage apparatusto pull sideways. Finally, a more uniformly tilled and level soilsurface is created.

The tillage apparatus allows for a larger amount of soil to be thrownthan with prior tillage apparatus, while leaving an even soil surface.The tillage apparatus is operable at high speeds in wet conditionswithout undue amounts of downtime due to blade breakage, seizure, orplugging.

While the foregoing provides certain non-limiting embodiments, it shouldbe understood that combinations, subsets, and variations of theforegoing are contemplated. The monopoly sought is defined by the claimswhich are intended to be construed broadly and limited only by thespecification.

What is claimed is:
 1. A tillage apparatus comprising: a frameconfigured to be moved in a longitudinal direction by a vehicle; and, aplurality of tillage assemblies, each tillage assembly having a concavedisc shaped tillage blade rotatably attached thereto configured in aplurality of transversely adjacent columns, the tillage assemblies ofthe plurality of columns arranged in at least four transverselyextending rows that are spaced apart along the longitudinal direction,each of the tillage assemblies being individually mounted to the frame,the concave blades of each column being transversely tilted from thelongitudinal direction left or right alternately by row, whereinlongitudinal spacing between a rearward adjacent pair of rows is greaterthan longitudinal spacing between a forward pair of rows, wherein ineach column the concave blade of a rearmost row is transversely tiltedless than the concave blade of a row forward of the rearmost row, theconcave blades of each column being transversely offset from one anotherto create a swath of tilled ground, wherein two of the concave blades ofeach column are at opposite transverse extents of a width of the column,and wherein the two concave blades are in adjacent rows and oppositelyoriented with respect to one another.
 2. The apparatus of claim 1,wherein at least one of the concave blades are tilted to throw a portionof soil onto a convex backside of a neighboring concave blade.
 3. Theapparatus of claim 1, wherein the concave blades in the rearmost rowhave a transverse tilt angle of about half of a transverse tilt angle ofthe concave blades in the rows forward of the rearmost row.
 4. Theapparatus according to claim 1, wherein the concave blades in therearmost row are transversely tilted at an angle in a range from about 4degrees to about 12 degrees.
 5. The apparatus according to claim 1,wherein the concave blades in the rows forward of the rearmost row aretransversely tilted at an angle in a range from about 12 degrees toabout 20 degrees.
 6. The apparatus according to claim 1, wherein theconcave blades in the rearmost row are vertically tilted at an angle ina range from about 4 degrees to about 12 degrees.
 7. The apparatusaccording to claim 1, wherein the concave blades in the rows forward ofthe rearmost row are vertically tilted at an angle in a range from about12 degrees to about 20 degrees.
 8. The apparatus according to claim 1,wherein spacing in the longitudinal direction between the rearmost rowand a row adjacent the rearmost row is greater than spacing in thelongitudinal direction between any pair of adjacent rows forward of therearmost row.
 9. The apparatus according to claim 1, wherein spacingbetween the rearmost row and the row adjacent the rearmost row isbetween about 1.5 and about 4 times the diameter of the concave blades,and wherein spacing between the forward adjacent pair of rows is betweenabout 1 and about 1.5 times the diameter of the concave blades.
 10. Theapparatus according to claim 1, further comprising a rearward set ofwheels to move the tillage apparatus in the longitudinal direction, theset of wheels mounted to the frame at a position forward of the rearmostrow and rearward of a row adjacent the rearmost row.
 11. The apparatusaccording to claim 1, wherein adjacent columns transversely overlap. 12.The apparatus according to claim 1, wherein the concave blades of eachcolumn are evenly transversely offset from one another by an offsetdistance equal to a width of the column divided by the number of rows.13. The apparatus according to claim 1, wherein the width of the columnis 20 inches.
 14. The apparatus according to claim 1, wherein the atleast four transversely extending rows of tillage assembliesindividually mounted to the frame comprises a first row, a second row, athird row and a fourth row and wherein the first row is adjacent to thesecond row, the second row is adjacent to the third row and the thirdrow is adjacent to the fourth row.
 15. The apparatus of claim 1, whereinthe tillage assemblies of the at least four transversely extending rowsare individually mounted to a common frame.